Question

Which of the following temperatures corresponds to the boiling point of water? a) \(0^{\circ} \mathrm{C}\) b) \(100^{\circ} \mathrm{C}\) c) \(0 \mathrm{~K}\) d) \(100 \mathrm{~K}\) e) \(100^{\circ} \mathrm{F}\)

Short answer

Answer: (b) 100°C

Step-by-step solution

Understand the boiling point of water

The boiling point of water is defined as the temperature at which water turns from its liquid form to its gas form or steam. This transition occurs at a specific temperature, and it is essential to be familiar with this constant value in various temperature scales.

Boiling point in Celsius scale

The most common temperature scale is Celsius, where the boiling point of water is \(100^{\circ} \mathrm{C}\). Therefore, option (b) can be the right answer.

Boiling point in Kelvin scale

The Kelvin scale is another widely used temperature scale, especially in scientific calculations. The Celsius and Kelvin scales have the same increments, but the Kelvin scale starts at absolute zero (-273.15 degrees Celsius). Thus, to convert Celsius to Kelvin, we add 273.15. The boiling point of water in the Kelvin scale is \(100^{\circ} \mathrm{C} + 273.15 = 373.15 \mathrm{~K}\). Neither option (c) nor (d) match this value, so they are not correct.

Boiling point in Fahrenheit scale

The Fahrenheit scale is another temperature scale used primarily in the United States. To convert temperatures from Celsius to Fahrenheit, we can use the following conversion formula: \(F=(9/5)C + 32\). Applying this formula to the Celsius boiling point, we obtain the Fahrenheit boiling point: \(F=(9/5)(100) + 32 = 212^{\circ} \mathrm{F}\). Option (e) does not match this value and is therefore incorrect.

Select the correct answer

Based on our analysis of the boiling point of water in various temperature scales, the correct answer corresponds to the boiling point in the Celsius scale, which is \(100^{\circ} \mathrm{C}\). Therefore, the correct answer is option (b).

Key concepts

Temperature Scales

Understanding different temperature scales is crucial when studying thermal properties like the boiling point of water. Each scale has its own starting point, units, and usage.

The Celsius scale, created by Anders Celsius, is widely used in most parts of the world and is based on the freezing and boiling points of water. The Kelvin scale, developed by Lord Kelvin, is essential in scientific work and starts from absolute zero, where all thermal motion stops, making it an absolute temperature scale. Meanwhile, the Fahrenheit scale, named after Daniel Gabriel Fahrenheit, is primarily used in the United States and some other regions for everyday temperature measurements.

Celsius Scale

The Celsius scale is denoted by degrees Celsius (). It defines the freezing point of water at and the boiling point at under standard atmospheric pressure. It's a straightforward scale that is simple to understand and convert to other temperature scales since it's based on a decimal system. Students find it accessible because they often encounter it in daily weather reports and cooking instructions.

Kelvin Scale

The Kelvin scale is the base unit of temperature in the International System of Units (SI). Unlike the Celsius and Fahrenheit scales, it does not use degrees but is simply expressed as Kelvin (K).

This scale measures . The freezing point of water on this scale is and the boiling point is . Due to its scientific importance, it's essential for students learning about temperature in a scientific context to understand Kelvin scale measurements.

Fahrenheit Scale

The Fahrenheit scale is used by those in the United States and a few other countries for everyday temperature measurement—it's a scale where water freezes at and boils at . To convert from Celsius to Fahrenheit, an understanding of the conversion formula is essential, a concept that may be less intuitive but is necessary for students to grasp in order to understand temperature data from different countries.

Phase Transition

Phase transition refers to the transformation of a substance from one state of matter to another, such as from liquid to gas. This occurs at the boiling point for a liquid turning into a gas.

For water, this happens at 100^{} ), at standard atmospheric pressure. This phase transition is not only important in everyday cooking and weather science, but also in industrial applications and scientific experiments where precise temperature measurements and understanding of matter states are crucial.